This invention relates to a programmable controller and, more particularly, to a controller in which different memory channels can be variously programmed.
Many systems, including processes, instruments, machines and the like, have been automated to the extent that they will automatically operate according to an input program. Such program may include various routines and subroutines or sequences. These routines and sub-routines are often controlled by a memory, typically a read only memory. One problem encountered with such systems is that it is somewhat difficult and time consuming to change or vary the various sub-routines.
One instrumentation system using a read only memory (ROM) is that described in U.S. Pat. No. 3,770,382 issued Nov. 6, 1973 to the same assignee as the subject invention. This patent describes an automatic clinical analyzer system in which the reagents for each test are contained in an analytical pack or plastic envelope which also serves as a reaction chamber and cuvette for a photometric analysis. Certain pack types may contain chromatographic columns to remove specific constituents. In any event a separate pack is used for each test performed on a sample. Each pack contains a digital code which is used to program the analyzer. The analyzer is programmed by inserting the appropriate packs containing the desired test indicia behind each sample cup in the input to the analyzer. The analyzer then automatically injects the proper amount of sample and diluent into each pack in succession, mixes the reagents, waits a pre-set length of time for the reaction to take place, forms an optical cell within the transparent pack walls and measures the reaction photometrically. These operations are controlled and monitored by a builtl-in, solid state, special purpose computer, and are performed under precisely regulated conditions. The heart of this computer is the hard wired ROM.
Since there are a very large number of tests which can be performed on a given sample, it is desirable that the computer be readily and easily programmable by the user such that processing of the packs may be varied to perform one or more of the many different tests on each sample.
Accordingly, it is an object of this invention to provide an improved programmable controller.
Another object of this invention is to provide an improved controller which can be programmed readily by the use of a read only memory having magnetic cores which can be selected by the user thereby to vary the program.
A further object of this invention is to provide an improved read only memory that is stable, of high reliability, and requires no power.